Skin-contacting articles, such as gloves, particularly medical gloves, are commonly used as a protective barrier against the contamination of the user by chemicals and body fluids containing micro-organisms including bacteria and/or viruses and the like. In addition, the gloves also protect the user from injuries that result from abrasive action. As such, these gloves and other skin-contacting articles are manufactured in such a way that they are entirely impermeable to the contaminants or microorganisms during use. To maintain this barrier integrity, gloves need to be free from defects, such as holes (e.g., pinholes) and tears.
The gloves also must have easy donning and doffing properties, particularly for medical glove applications, where the time available for glove donning can be a matter of seconds. There are three specific aspects of donning properties related to medical gloves, more specifically surgical gloves, namely dry hand donning, damp-hand or wet-hand donning, and double gloving. If the user encounters difficulty in donning a glove, normally the user will give up donning of the particular glove and try to select a glove that provides superior donning properties. Surgical glove users normally wash their hands before donning the gloves. In most cases, their hands are either damp or wet when donning the gloves is attempted. In many cases, gloves are double donned, one glove on top of the other, in order to provide an additional glove barrier layer. If the outer glove tears or is cut, the surgeon can simply remove the outer glove without having to wash hands and start the glove donning process all over again, a task which takes additional time during surgery. Therefore, the double donning or double gloving properties are extremely important. To achieve good double gloving properties, the inside surface of the outer glove and the outside surface of the inner glove need to be smooth so that they can easily slide against each other. However, the outside surface of the glove should not be too smooth, as this would result in poor grip properties, causing difficulty to the user in holding or handling surgical instruments. Therefore, the outside surface of the gloves should have a certain level of tack for providing good grip properties and yet not cause difficulty in double gloving to the user, while the inside surface of the gloves should be as smooth as possible.
The processes of donning and glove flexing during use involve stretching. Therefore, it is important that the gloves, particularly medical gloves, are stretchable, i.e., have tensile properties good enough to prevent tearing or breakage during donning or use. Any coatings applied to the glove for easy donnability should not interfere with the tensile properties and stretch properties of the rubber elastomer of the glove.
Other important properties of gloves, particularly surgical gloves, include a good comfortable feel during use. To achieve this, the gloves must fit well without bagginess contouring the shape of the hand. The glove is stretched over the hand surface with a nearly uniform stretch everywhere with no particular area being stretched more than other areas, since this highly stretched area will result in a pinching glove feel. This proper glove fit is designed into the glove shape by using a former with the shape of the hand. In addition, the elastomeric materials used for the glove must be soft and stretchable so that the hands experience minimal stress while using them. Unfortunately, soft materials, such as natural rubber and polyisoprene, are normally tacky and, therefore, require a surface treatment, such as chlorination, siliconization, or a polymer coating to circumvent this inherent tackiness. The polymer coating process laminates the surface of the glove with a thin layer of synthetic polymer, normally up to several micrometers in thickness, having a low-friction coefficient value to provide anti-tack and good slip properties, as disclosed in U.S. Pat. No. 6,709,725 to Lai et al., which discloses a natural or synthetic rubber elastomeric article having a coating layer containing a blend of a film-forming polymer and a wax. A powder-free glove article also can be made without chlorination, using a powder-free coagulant system as disclosed in U.S. Pat. No. 6,352,666 to Nile et al., which discloses a process for the manufacture of rubber articles. In this disclosure, a powder-free coagulant for use in latex dipping processes comprises a salt-stable dispersion of a polychloroprene rubber and an inorganic metal salt and a powder-free release agent comprising a polypropylene wax emulsion and a cationic surfactant.
In addition, the cuff of the glove should not slip or roll down during use. If this happens, the user's hand becomes exposed and the chemicals or biological fluids can contaminate the user.
Apart from these properties, it is also essential for the glove or its surfaces to be hand-friendly to the user, especially medical gloves, where the glove is worn for a period of 1-2 hours. Since the glove is a barrier, the skin-generated moisture is trapped between the user's skin and the latex barrier layer of the glove. The latex barrier layer of the glove should contain little or no skin irritants, such as sodium dodecyl sulphate, a commonly used surfactant, or calcium nitrate, a commonly used coagulant, or allergens, such as rubber accelerators and latex proteins, which are other rubber-processing chemicals that can cause skin irritation and allergenic reactions. It is known that healthcare workers commonly wash their hands very often to maintain their hand hygiene. This causes the removal of the protective layer of lipids from the skin and, therefore, the natural skin moisturizer is lost. When the glove is removed, the skin-generated moisture dries rapidly, and the hands quickly become very dry. After prolonged use of a glove, the skin becomes over-dry and cracks can occur. The formation of cracks allows microorganisms, allergens and other harmful substances to enter the body, resulting in skin problems and overall health problems. To address this issue, it has been suggested to apply a moisturizer and other skin-protecting or skin-repair agents to the inner surface of the glove during the glove manufacturing process. However, the application of the moisturizer can have adverse effects on the properties of the glove, including deterioration of the tensile strength of the rubber barrier layer, the wet-look of the inside of a glove, or the blocking of the glove inner surfaces, wherein the inside surfaces of the glove stick to each other, causing difficulty in donning the glove.
U.S. Pat. No. 5,614,202 to DeFina discloses a multi-layer moisturizing glove. The middle layer of the glove is saturated with lotion, which can migrate to the user's hand through the pores of the inner layer, while the exterior layer is made of non-porous material. However, there is no formulation given in the patent.
U.S. Pat. No. 6,638,587 to Wang et al. discloses an elastomeric article having a silicone-based composite coating. An elastomeric article, such as a latex glove, is coated with an aqueous dispersion containing a composite of a silicone-modified polymer, e.g., a silicone-modified polyurethane, and silicone resin particles integrated therein. The interaction between the silicone groups on both the polymer and particles enhances the effectiveness of binding of the particles to the latex material. Gloves and other articles contain a micro-roughened skin-contacting surface and exhibit a reduced coefficient of friction and increased lubricity, thereby enhancing the donning properties. There is no indication that the coating protects skin moisture.
U.S. Pat. No. 6,787,490 to Shipp discloses a glove donning delivery system. A cellulosic substrate includes a flexible, substantially planar sheet of at least one layer. The layer has a front side and a backside with a donning agent associated with at least one side of the sheet. The donning agent is transferable from the sheet to an object or individual apart from the sheet. The donning agent is a biocompatible and sterilizable composition and contains a wetting agent, a silicone, skin health agents, residual antimicrobial substrate agents, antimicrobial agents or aloe vera, vitamin E and emollients. The coating is applied to a cellulosic material, not to a rubber elastomeric product.
U.S. Pat. App. Pub. No. 2004/0115250 to Loo et al. discloses a chamomile/aloe vera treated glove. The treating solution comprises water, glycerol, and a botanical extract for applying to the inner surface of a glove. However, there are no lubricants and surfactants in the formulation.
U.S. Pat. App. Pub. No. 2004/0115379 to Conley et al. discloses a method of treating an elastomeric article. This method includes providing a flexible non-woven fabric substrate having a treatment comprising a behenetrimonium methosulfate, distearyldimonium chloride, and dimethyl dioctadecyl ammonium chloride surfactant. The elastomeric article has an exposed surface, which is the external surface of the elastomeric article. When the elastomeric article is placed with the substrate into a tumbling apparatus, and tumbled at a temperature between 20-80° C., the treatment is transferred from the substrate to the exposed surface of the elastomeric article. The elastomeric article is then inverted and the interior surface is exposed and is tumbled with a silicone lubricant. The surfactant coating on the exterior surface of the elastomeric article is only a surfactant and may improve double donning of a glove. The silicone coating is oily and spreads poorly on the glove inner surface and at best enables easy donning of a glove. It does not help moisture retention and has a clammy glove feel.
U.S. Pat. App. Pub. No. 2004/0217506 to Vistins discloses a method of treating a partially solidified elastomeric matrix. This method provides a transfer substrate of open cell or non-woven material that includes a treatment. The treatment comprises an emollient, a humectant, a skin conditioner, an extract and silicone lubricant or skin health agents. The elastomeric matrix has an exposed surface and contacting the matrix with the transfer substrate transfers the treatment from the substrate to the exposed surface of the elastomeric matrix. Transferring these treatment agents to the exposed surface of a partially solidified elastomeric matrix does not guarantee that any of the treatment agents survive the glove manufacturing process, which includes heating, several stages of washing, and chlorination or other chemical treatments. Besides, the very action of contacting a partially solidified elastomeric matrix on a former and peeling of the substrate may produce holes and other defects on the elastomeric matrix, which is unacceptable in a glove, which is relied on as a barrier layer.
Int'l Pat. App. Pub. No. WO 2004/037305 A1 and U.S. Pat. App. Pub. No. 2004/0126604 to Wang et al. disclose a coating composition for the skin-contacting surface of an elastomeric article. The therapeutic, moisturizing coating composition is thermally stable, withstanding 70° C., and subsequently hydrates when contacted with a moisturized skin surface to convert into a liquid “lotion” form during wearing of the article. Therefore, the coating is not inherently ‘moisturizing’ but requires skin perspiration to activate the coating. The moisturizer composition consists of a polyhydric alcohol moisturizer, which is pantothenol, glycerin or sorbitol, and an alphahydroxy lactone, which is gluconolactone, which is water soluble and hydratable upon contact with skin. The composition further comprises a water-soluble, film-forming polymer, which is chitosan. For damp-hand or wet-hand donning properties, 1% cetyl pyridinium chloride (CPC) is added to the mixture. There are no water-insoluble emollients in this composition.
U.S. Pat. App. Pub. No. 2004/0241201, which is a continuation of U.S. Pat. App. Pub. No. 2004/0126604, discloses a coating composition containing a hydration promoter and a water-soluble moisturizer, or a water-soluble moisturizer and a water-soluble film forming polymer, or a water-soluble moisturizer and an exfoliant, or a water-soluble moisturizer and microporous particles. However, there are no lubricants to facilitate donning and occlusive moisturizer to promote spreading of the coating in the formulation.
Int'l Pat. App. Pub. No. WO 2004/060338 to Lew et al. discloses a topical skin-care formulation (TSF) and dipped elastomeric rubber polymer articles produced using the TSF. The TSF includes effective amounts of Vitamins A, B and E, alpha-lipoic acid, eucalyptus, jojoba and a carrier, such as an emollient cream, and protects and soothes the human's skin, which is in contact with the surface of the dipped elastomeric rubber polymer article. This oil-based formulation may be applied to a dipped elastomeric article after the final washing step and dried to evaporate water to form a substantially uniform coating. This coating is for dipped elastomeric rubber polymeric articles, such as rubber gloves and condoms, and has the ability to provide the user with the benefits of added protection, due to the coating materials, such as moisturizing, protective and antiseptic properties, and also improved comfort, due to soothing and cooling effects. Non-sterile dipped elastomeric rubber polymeric articles coated with TSF have been shown to have lower bacterial counts than similar uncoated dipped elastomeric rubber polymeric articles. The coating material is claimed not to impair the physical properties of the dipped elastomeric rubber polymeric articles. The composition contains 10-50% emollient cream, which is a carrier, for applying onto the surface of gloves. The drawback of the proposed formulation is that it contains too high a level of emollient, which is normally an oil. Soaking natural rubber and polyisoprene gloves in the high oil content mixture could cause swelling and deterioration in the physical properties of the gloves.
Int'l Pat. App. Pub. No. WO2004/060432 and U.S. Pat. App. Pub. No. U.S. 2004/0122382 to Johnson et al. disclose elastomeric articles with a beneficial coating on the surface. The coating separates from the glove surface and transfers to the skin and emulsifies due to skin-generated moisture. The coating includes a carrier, which is a self-emulsifying wax, and a quaternary ammonium compound behenetrimonium methosulfate. The coating also includes an additive selected from the group consisting of an emollient, a humectant, an antioxidant, a neutralizing agent, a chelating agent, an anti-irritant, a vitamin, a skin conditioner, an alpha-hydroxy acid, a moisturizer, a beneficial botanical agent, and an extract. In addition, the carrier may contain dimethicone silicone polymer. However, this silicone polymer is insoluble in moisture, defeating the self-emulsification of the carrier. This coating relies on the skin-generated moisture to separate the carrier and disperse the beneficial agent on the skin as the carrier emulsifies. There are no active lubricants or surfactants in this composition and, as a result, the distribution of the coating on the skin surface is poor.
Patent Application JP2004/190164 to Ochi et al. discloses novel gloves having the effect of positively moisturizing the skin of the wearer's hand as well as only protecting the hand from stimulation from outside, or reducing stimulation from the glove itself. The glove is formed of rubber or resin, and retains urea at least on the inner surface thereof. The urea is preferably contained in the glove itself, and it is more preferable that the content of the urea is 0.1-10 wt. %. However, the formulation contains no occlusive moisturizer or surfactant for promoting spreading of the coating and a lubricant for facilitating donning of the glove.
Int'l Pat. App. Pub. No. WO2005/036996 and U.S. Pat. App. Pub. No. 2005/0081278 to Williams disclose a polymeric glove with a lotion coating and a method of making same. This disposable glove comprises a polymeric material having an inside surface for contacting the skin of a wearer coated with a film-forming polyurethane compound and an oil-based emollient comprising petrolatum, cetearyl alcohol, cetyl alcohol, C12-15 alkyl Benzoate, cyclomethicone or Ceteareth 20. A method of making the glove is also disclosed. These petroleum and oil-based emollients do not disperse easily in an aqueous coating and cause natural and synthetic rubber articles to swell and, therefore, result in the degradation of tensile strength and elongation properties. In addition, there is no water-soluble moisturizer in the formulation. Furthermore, the use of film-forming polyurethane in the formulation will make it difficult to apply the coating by the off-line tumbling and drying method. This is because the polyurethane, when dried, will stick to the dryer, and this will make subsequent dryer cleaning difficult.
There remains a need in the art for a hand-friendly coating, which coats the hand-contacting surfaces of gloves and facilitates dry donning, wet donning and double donning, while still providing adequate glove-grip properties so that surgical implements can be effectively handled. The coating composition desirably prevents rapid drying of skin-generated moisture when the glove is removed and prevents cracking of skin, thereby providing a protective hand-friendly coating layer. The coating composition desirably does not damage the rubber elastomeric article and compromise its tensile and stretch properties. It is an object of the present invention to provide such a coating as well as a glove comprising such a coating and methods of making such a composition and glove. These and other objects and advantages of the present invention, as well as additional inventive features, will become apparent from the detailed description provided herein.